Multi-shut-in tool



Dec. 19, 1967 D. R. REARDON 3,358,767

MULTI-SHUT-IN TOOL Filed Aug. 2'7, 1965 3 Sheets-Sheet 1 IHP PRE$5URE D D 2 8 P D FFP I I 3 IFP Z F -TIM DANIEL R. REARDON.

INVENTOR.

ATTORNEY.

Dec. 19, 1967 D. R. REARDON 3,358,767

MULTI-SHUT- IN TOOL AT TORNE Y.

United States Patent 3,358,767 MULTI-SHUT-IN TOOL Daniel Richard Reardon, Garden Grove, Calif., assignor to Cook Testing (10., a corporation of Nevada Filed Aug. 27, 1965, Ser. No. 483,131 2 Claims. (Cl. 166-152) ABSTRACT OF THE DISCLOSURE A shut-in tool having telescopic valve means including outer and inner tubular mandrels for controlling the operation of a test tool assembly in testing a deep well, the outer mandrel forming a cylinder with a closed end and the inner mandrel forming a piston with a closed end, there being passage means in the outer mandrel to admit well fluid into the chamber formed between the closed end of the outer mandrel and said piston to exert a preponderant hydrostatic force downwardly on the inner mandrel and from this against a hydraulic valve tool of said assembly disposed therebeneath thereby maintaining the latter tool in open position while the shut-in tool is repeatedly shifted between open and closed positions during the test.

Background of the invention (1) Field of invention: Improving the effectiveness of apparatus employed in deep well formation testing.

(2) Description of the prior art.

It is conventional procedure in conducting a deep well formation test to employ a test tool assembly which is suspended from a drill string and includes, among other elements, and in order from the top downward, a shut-in valve tool, a hydraulic valve tool, an open hole packer, a perforated tail pipe and a recorder carrier.

The well is normally filled with rotary mud and the drill string is empty when going into the well, with the test tool assembly suspended thereon. The recorder graphically records the pressure of the surrounding fluid throughout the test. The tail pipe admits said fluid upwardly through the packer, the hydraulic valve tool and the shut-in valve tool into the lower end of the drill string, when said valve tools are both open, but these tools are both closed by the weight of the tool assembly while the latter is being lowered into the well.

The first recording of significance is the Initial Hydrostatic Pressure which is that of the fluid surrounding the recorder carrier when the latter comes to rest on the bottom of the well.

Each of the valve tools is telescopic and is opened, after the recorder carrier touches bottom, by cautiously continuing the lowering of the drill string. The shut-in tool offers little resistance to opening and thus its valve opens before that of the hydraulic valve tool which includes a hydraulic dash pot which delays its opening until sufiicient downward pressure has been applied through the valve tools to the packer to set the latter in the well bore and thus pack-off the test area located between the packer and the well bottom.

The setting of the packer and opening of the hydraulic valve tool completes the sealing off of the test area at the bottom of the well from the column of rotary mud surrounding the drill string above the packer and opens communication between the packed off test area and the lower end of the empty drill string.

The next significant pressure in the test, known as the First Initial Flow Pressure, is now recorded.

After a short period during which the pressure generally increases slightly due to the rise in fluid level in the drill string, to a value termed the First Final Flow Pressure, the drill string is raised to shut the shut-in valve tool, thus shutting in the fluid in the test area below the packer so as to develop the pressure latent in the adjacent formation due to fluids normally flowing from this formation into the well. When this pressure levels off it is termed the First Initial Shut-in Pressure.

The drill string is now lowered to open the shut-in tool thereby reconnecting the test area with the interior of the drill string, the pressure thereupon dropping rapidly to a value slightly above the First Final Flow Pressure, and which is termed the Second Initial Flow Pressure.

A flow period of substantial length is now allowed to elapse during which fluids entering the test area from the surrounding formation flow upwardly through the valve tools and into the lower portion of the drill string. The Second Final Flow Pressure is that recorded at the end of this period, and generally indicates a sample of substantial magnitude having been received by the drill string.

At the conclusion of the last mentioned free flow period, the drill string is again lifted just enough to close the shut-in tool and seal off the test area against the escape of fluid therefrom. This causes the pressure to rise to a value generally the same or slightly less than the Initial Shut-in Pressure and is known as the Second or Final Shut-in Pressure. This ordinarily concludes the pressure recordings taken in the formation test and is followed by withdrawal of the drill string and tool assembly from the well.

When closed against a flow of fluid upwardly there through, the hydraulic valve tool opens an auxiliary valve which sets up a communication between the test area below the packer and the well bore above the packer. This .equalizes the pressures in these areas just before pulling Summary of, the invention It is an objectof the present invention to provide a shut-in valve tool in which the tension required to telescopically extend and thus shut the same is substantially uniform under all foreseeable operating conditions 'and is less, by a comfortable margin, than the tension required to close the hydraulic valve tool.

Another object of the inventon is to provide such a shut-in tool which, in addition to its function as above described, facilitates the regulated delivery of a liquid or of a gas, such as nitrogen, downwardly through said drill string into the test area under extremely high pressures.

Brief description of the drawings The manner of accomplishing the foregoing objects as well as further objects and advantages will be made ma'nifest in the following description taken in connection with the accompanying drawings in which:

FIG. 1 is a diagrammatic vertical section view of an oil well and illustrates a formation test tool assembly which includes a preferred embodiment of the shut-in tool of the invention, being lowered in the said well with said assembly suspended on the lower end of the drill string and just prior to contact of said tool assembly with the bottom of the well.

FIG. 2 is a view similar to FIG. 1 and illustrates an advanced stage in said formation test after the test tool assembly has come to rest on the bottom of the well and the downward movement of the drill string has been continued so as to telescopically collapse and thus open the shut-in tool, expand the packer so as to pack oil the test area at the lower end of the well, and then to telescopi cally collapse the hydraulic tool so as to open this and establish axial fluid communication between the perforated tail pipe below the packer and the lower end of the drill string.

FIG. 3 is a horizontal cross sectional view taken on the line 33 of FIG. 6a and shows the relative location of the passages provided in the upper sub of the tool of the invention.

FIG. 4 is a horizontal cross sectional view taken on the line 4-4 of FIG. 7b and illustrates the splined connection between the outer and inner mandrels of the invention.

FIG. 5 is a diagrammatic illustration of a continuous graphic record of the pressures developed during the aforesaid test at the lower end of said test tool assembly.

FIG. (FIG. 6a and FIG. 6b) is an enlarged vertical sectional view of the shut-in tool of the invention taken on the line 6-6 of FIG. 1 and showing said tool telescopically extended as when the tool assembly is being lowered into the well.

FIG. 7 (FIG. 7a and FIG. 7b) is a view similar to FIG. 6 and is taken on line 77 of FIG. 2 and illustrates the tool of the invention when this is telescopically collapsed to open the telescopic valve thereof to permit an axial flow in either direction of fluid through said tool.

Description of the preferred embodiment Referring specifically to the drawings and particularly to FIG. 1, an open oil well bore 10 having a bottom 11 is here shown which penetrates at its lower end into an oil bearing formation 12. A formation test tool assembly 13 is shown in this view as being lowered into the well bore 10 suspended on the lower end of a drill string 14.

The test tool assembly 13 embodies, among other elements, and naming these from the top downward, a shutin tool 15, comprising a preferred embodiment of the invention, a hydraulic valve tool 16, an open hole packer 17, a perforated tail pipe 18 and a recorder carrier 19. The elements thus specifically enumerated as being embraced in the tool assembly 13 are conventional with the exception of the hydraulic valve tool 16 and the shut-in valve tool 15. The valve tool 16 may be of the type disclosed in the co-pending application Ser. No. 374,685, filed June 12, 1964, by Wayne N. Sutlifi, entitled Testing Tool, now US. Letters Patent No. 3,295,- 607. The shut-in valve tool 15 constitutes a preferred embodiment of the present invention and, for a specific description of the structure thereof, reference is now made to FIGS. 6 and 7.

The principal elements of the shut-in tool 15 are an outer mandrel 2S and an inner mandrel 26, the latter being telescopically slidable within said outer mandrel. The outer mandrel includes a sub 27 having a blind bore 28 and terminates at its upper end in a threaded box 29 for receiving a pin 30 at the lower end of the drill string 14 for suspending the test tool assembly 13 thereon. The sub 27 has external threads 31 and provides a downwardly extending head 32 of reduced diameter so that this head is placed inwardly from and coaxial with an outer mandrel shell 33- which screws onto the theads 31. Provided in the sub 27 and connecting the blind bore 28 with the annular space between the head 32 and the outer mandrel shell 33 are a plurality of relatively large passages 34, preferably seven in number, as shown in FIG. 3. Another smaller passage 35 is provided in the sub 27 which extends from the bottom face of the head 4 32 upwardly between the blind bore 28 and threads 31 and opens outwardly through the outer surface of the sub 27. The periphery of head 32 is turned down to form a cylindrical seat 36 terminating upwardly in an 'annular shoulder 37, said seat being sealed with two O-rings 38.

The outer mandrel shell 33 is provided with external tapering threads 40 at its lower end and has a short bore 41 located within the lower portion of said threads and a longer counter bore 42 extending upwardly therefrom to form an annular shoulder 43. At its upper end the counter bore 42 connects with a still longer counter bore 44. Slidably fitting at its lower end within the counter bore 42 against the shoulder 43 and slidably fitting onto the cylindrical seat 36 against the shoulder 37 at its upper end is a cylindrical sleeve 45. This sleeve is externally annularly grooved near its lower end to receive O-rings 46 and has four equally spaced holes 47 which communicate with the annular space 48 between the sleeve 45 and shell 33 and the purpose of which will be made clear hereinafter.

The outer mandrel 25 also includes an outer spline sub 49 which screws upwardly onto the threads 40 and has an inwardly extending shoulder 50 at its lower end which is provided with diametral spline slots 51. Suitable ports 55 are provided in the outer splined sub 49 for a purpoose to be made clear later.

The inner mandrel 26 includes a lower sub 56 having a bore 57 and pin threads 58 at its lower end by which the tool 15 is connected to the hydraulic valve tool 16. At its upper end sub 56 has internal threads 59 into which the threaded lower end of inner tubular spline sub 60 screws. This sub has diametral splines 61 which terminate at their upper ends in an annular shoulder 61a. Splines 61 extend into and make splined engagement with spline slots 51 of the outer spline sub 49. The spline sub 60 has a bore 62 which terminates at its upper end in a counter bore 63 having threads 64 into which the lower end of a tubular plunger 65 is screwed to as to trap an O-ring 66 in counter bore 63.

The tubular plunger 65 is slidably received by the sleeve 45 in the outer mandrel 25 and is internally threaded at its upper end to receive a plug 70 screwed downwardly therein. Provided in the outer surface of the plunger 65 is a relatively shallow annular recess 71 which is disposed opposite the four holes 47 in the sleeve 45, when the tool 15 is telescopically extended as shown in FIG. 6. Some distance below the recess 71, said plunger is provided with a relatively large annular external recess 72, the plunger being provided with four equally spaced holes 73 within the area of recess 71 and with four somewhat larger holes 74 within the area of the recess 72. The outer surface of plunger 65 is also provided with suitable narrow annular recesses for accommodating two O-rings 75 just below recess 72, four O-rings 76 located between recesses 72 and 71 and two O-rings 77 located above recess 71.

Below the threads 7011 by which plug 70 screws into the upper end of tubular plunger 65, said plug makes a sliding fit with the interior of said plunger and extends downwardly below the level of the four equally spaced holes 73 formed in said plunger. Extending upwardly into said plug is a blind bore 78, the plug having a central tapped hole 79 extending upwardly from said bore for the reception of the threaded upper end of a valve guide shaft 80. At the lower end of bore 7 8 the plug 70 is beveled to provide a valve seat 85. In the area of the four holes 73, the plug 70 is provided externally with an annular recess 86 and four holes 87 are provided in the wall of the plug 70 communicating between the recess 86 and the bore 78 of said plug. The plug 70 is provided with narrow annular channels in its outer surface just above and below the recess 86 to accommodate O-rings 88. Slidable on the shaft and slidably fitting into the bore 78 and against the seat is a poppet check valve 89 which is yieldably pressed upwardly againstsaid seat by a coiled spring 90 encircling the shaft 80 and trapped in place by a washer 91 and nut 92 applied to the threaded lower end of said shaft. The check valve 89 is provided with external and internal O-rings 93 and 94 for forming a fluid-tight seal between said valve and the bore 78 and shaft 80 respectively.

Operation As will readily be seen by comparison of FIGS. 6 and 7, the shut-in valve tool 15 of the invention will be telescopically elongated when the test tool assembly 13 is suspended from the drill string 14 as when running the same into the well and this places the four holes 47 in the cylindrical sleeve 45 out of communication with the four holes 74 in the tubular plunger 65 and thus shuts off said tool against any flow of fluid upwardly therethrough. It also shuts off this tool against any fluid flow downwardly therethrough excepting where this is under relatively high pressure so as to compress coil spring 90 and thus open the poppet valve 89 by forcing said valve downwardly out of the blind bore 78 of the plug 70. In conventional testing, the drill string 14 is empty at the start of a test, and the space therein is at atmospheric pressure. Under these circumstances, there is no force then present in the shut-in tool 15 which would open the valve 89. In fact the valve 89 is provided especially for use in those exceptional cases where an inflatable packer is used in the test tool assembly which requires that a liquid or gas must pass downwardly through poppet valve 89 to inflate the packer.

As already described, the test of formation 12 begins with the test tool assembly 13 coming to rest on the bottom 11 of well bore as shown in FIG. 2 which results, in rapid succession, (l) in the shut-in tool telescopically collapsing, (2) in the open hole packer 17 expanding as shown in FIG. 2 and then (3) in the hydraulic valve tool 16 telescopically collapsing. As pointed out in the preamble of this application, the steps of the formation test which follow the condition shown in FIG. 2 involve principally the repeated lifting of the drill string to close the shut-in tool 15 and, after an interval, lowering of the drill string to open said shut-in tool. As stated, it is of great importance that the rig operator can be certain that when he lifts the drill string from its lowermost position a sufiicient distance to telescopically extend and thus shut oil" the shut-in tool 15, that this tool will respond as desired. For this to occur, the forces applied downwardly to the inner mandrel 26 must be suflicient to prevent this from telescopically extending the hydraulic valve tool 16, and thereby set up a free communication between the well bore area below the packer and that above the packer.

This very desirable characteristic is attained in the shut-in valve tool 15 by connecting the chamber 95 formed in the upper end of the sleeve 45 between the tubular plunger 65 and the head 32 of sub 27 with the surrounding well fluid by the small passage 35 provided in said sub. This passage admits fluid from the well bore area above the packer 17 into chamber 95 so that a relatively high hydrostatic pressure is applied downwardly against the plug 70 of the plunger. The reason for this downward pressure being relatively high is because the fluid in the well bore area above the packer 17 is at the bottom of a column of mud extending to the top of the well, whereas the fluid pressure in the sealed off portion of the well bore below the packer 17 is relatively low because this area is connected with the empty space within the drill string 14 from which the testing tool assembly 13 is suspended, and this space is approximately at surface atmospheric pressure. This excessive downward pressure on the inner mandrel of the shut-in tool holds the hydraulic valve tool 16 in its status quo and thus permits the shut-in tool 15 to be telescopically elongated without disturbing the collapsed open condition of the hydraulic valve tool 16. It is because of the dependability 'of the present invention in the particular regard above noted that it is termed a multi-shut-in tool as it facilitates making any number of closing and opening operations of this tool during a single test as indicated in the pressure graph shown in FIG. 5. This graph illustrates a typical formation test in which the latter was protracted to allow for at least three free flow periods, thus substantially supplementing the sample obtained in the test and helping establish the reservoir depletion rate.

As shown in FIGURE 5, the 3rd shut-in period tapers olf at a final shut-in pressure FSI. Here the drill string is further lifted to extend the hydraulic valve tool of the testing assembly, which tool thereupon connects the packed ofl area below the packer 17 with the well bore thereabove in preparation for collapsing the packer and withdrawing the testing assembly from the well. This produces the final hydrostatic pressure on the pressure recorder indicated on the graph as FHP. A short time following this step, the withdrawal from the well of the testing assembly starts, during which withdrawal the pressure recorded in said assembly returns to atmospheric as indicated at the left end of the graph in FIGURE 5.

The shut-in tool 15 has the added feature of providing, in the check valve 89 thereof, the opportunity for the rig operator to deliver a fluid or a gas, such as nitrogen, under high pressure downwardly through the shut-in tool 15, while the latter is otherwise closed as shown in FIG. 6, and having this fluid trapped by said tool against return upward so as to conduct the test in the test area below the packer 17 at a substantially elevated pressure. When the valve 89 is so used it is always possible to relieve the test area of this added pressure merely by lowering the drill string so as to open the shut-in tool 15 for restoring free axial communication through said tool.

While only a single embodiment of the invention is disclosed herein it is to be understood that this is for exemplary purposes only and that various changes and modifications may be made in the structure illustrated without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. A shut-in tool for use in deep well formation test ing, When incorporated sequentially with other elements of a test tool assembly, which assembly includes a hy draulic valve tool and a well bore packer and is suspended on the lower end of a drill string, said shut-in tool comprising: telescopic valve means including telescopically slideable outer and inner mandrels; means for connecting said mandrels to contiguous elements of said test tool assembly, said valve means controlling axial flow through said shut-in tool and being shut olf by the telescopic extension of the tool when said assembly is suspended, and being opened by the telescopic contraction thereof as effected by lowering said string after said assembly has come to rest on the well bottom; sleeve means in said outer mandrel an end of which is closed to form a cylindrical chamber into which an end of said inner mandrel slideably extends, said end of said inner mandrel also being closed so as to act like a piston in said chamber; means for connecting the other end of said inner mandrel to an element of said tool assembly which conducts fluid to said shut-in tool from a test area portion of a well bore which is packed-01f from the rest of the latter by said packer, whereby the hydrostatic pressure of the fluid within said packed-ofl. area is applied upwardly against said inner mandrel; and passage means in said outer mandrel admitting well fluid having a substantially higher hydrostatic pressure from above said packer into said closed end of said chamber into hydrostatic pressural contact with the closed end of said inner mandrel, a preponderantly downward hydrostatic pressure thus being applied to said inner mandrel, whereby said telescopic valve means of said shut-in tool may be closed and reopened repeatedly during a formation test program without disturbing the collapsed open condition of the draulic valve tool of said assembly.

2. A shut-in tool as recited in claim 1 wherein an auxiliary valve means is provided which is spring biased into closed position to halt upward axial flow at any time through said auxiliary valve means but is operative, when the aforesaid telescopic valve means is closed, to provide an axial passage for downward flow only, through said tool, said auxiliary valve means checking return flow therethrough whenever said downward flow ceases.

- 8 References Cited UNITED'STATES PATENTS Park s 166-152 5 2,128,716 8/1938 Smith 1661S2 2,657,895 11/1953 Huber et al. 166--152 2,690,807 10/1954 Moosman 166-152 3,190,360 6/1965 Farley 1661S2 10 JAMES A. LEPPINK, Primary Examiner. 

1. A SHUT-IN TOOL FOR USE IN DEEP WELL FORMATION TESTING, WHEN INCORPORATED SEQUENTIALLY WITH OTHER ELEMENT OF A TEST TOOL ASSEMBLY, WHICH ASSEMBLY INCLUDES A HYDRAULIC VALVE TOOL AND A WELL BORE PACKER AND IS SUSPENDED ON THE LOWER END OF A DRILL STRING; SAID SHUT-IN TOOL COMPRISING: TELESCOPIC VALVE MEANS INCLUDING TELESCOPICALLY SLIDEABLE OUTER AND INNER MANDRELS; MEANS FOR CONNECTING SAID MANDRELS TO CONTIGUOUS ELEMENTS OF SAID TEST TOOL ASSEMBLY, SAID VALVE MEANS CONTROLLING AXIAL FLOW THROUGH SAID SHUT-IN TOOL AND BEING SHUT OFF BY THE TELESCOPIC EXTENSION OF THE TOOL WHEN SAID ASSEMBLY IS SUSPENDED, AND BEING OPENED BY THE TELESCOPIC CONTRACTION THEREOF AS EFFECTED BY LOWERING SAID STRING AFTER SAID ASSEMBLY HAS COME TO REST ON THE WELL BOTTOM; SLEEVE MEANS IN SAID OUTER MANDREL AN END OF WHICH IS CLOSED TO FORM A CYLINDRICAL CHAMBER INTO WHICH AN END OF SAID INNER MANDREL SLIDEABLY EXTENDS, SAID END OF SAID INNER MANDREL ALSO BEING CLOSED SO AS TO ACT LIKE A PISTON IN SAID CHAMBER; MEANS FOR CONNECTING THE OTHER END OF SAID INNER MANDREL TO AN ELEMENT OF SAID TOOL ASSEMBLY WHICH CONDUCTS FLUID TO SAID SHUT-IN TOOL FROM A TEST AREA PORTION OF A WELL BORE WHICH IS PACKED-OFF FROM THE REST OF THE LATTER BY SAID PACKER, WHEREBY THE HYDROSTATIC PRESSURE OF THE FLUID WITHIN SAID PACKED-OFF AREA IS APPLIED UPWARDLY AGAINST SAID INNER MANDREL; AND PASSAGE MEANS IN SAID OUTER MANDREL ADMITTING WELL FLUID HAVING A SUBSTANTIALLY HIGHER HYDROSTATIC PRESSURE FROM ABOVE SAID PACKER INTO SAID CLOSED END OF SAID CHAMBER INTO HYDROSTATIC PRESSURAL CONTACT WITH THE CLOSED END OF SAID INNER MANDREL, A PREPONDERANTLY DOWNWARDLY HYDROSTATIC PRESSURE THUS BEING APPLIED TO SAID INNER MANDREL, WHEREBY SAID TELESCOPIC VALVE MEANS OF SAID SHUT-IN TOOL MAY BE CLOSED AND REOPENED REPEATEDLY DURING A FORMATION TEST PROGRAM WITHOUT DISTURBING THE COLLAPSED OPEN CONDITION OF THE HYDRAULIC VALVE TOOL OF SAID ASSEMBLY. 